Arrays & Strings - Quiz

Which declaration correctly creates an array of 10 integers initialized to 0?

Given int scores[5]; as a local variable, what is the state of its elements before explicit initialization?

Which 2D array declaration best represents a 3x4 grid of pixels?

How is the null terminator represented in a C-style string?

Which header must be included to use std::string?

Which operation safely concatenates two std::string objects?

What is sizeof(greeting) if char greeting[] = "Hi";?

Which access to a 2D array matrix[3][4] is valid?

Given std::string s = "abc"; what does s.length() return?

Which is the safest way to copy a C-style string into a fixed-size buffer?

Declare a 2D array of 3 rows and 4 columns of int named matrix

Initialize a C-style string with automatic null termination

Append lastName to firstName using std::string

What is the output of this code?

1#include <iostream>
2int main() {
3    int arr[5] = {1, 2, 3};
4    for (int i = 0; i < 5; ++i) {
5        std::cout << arr[i] << " ";
6    }
7    return 0;
8}

What does this program print?

1#include <iostream>
2#include <string>
3int main() {
4    std::string s = "C++";
5    s += " Programming";
6    std::cout << s.size() << " " << s[0] << " " << s.back() << "\n";
7    return 0;
8}

What is the output?

1#include <iostream>
2#include <cstring>
3int main() {
4    char src[] = "Hello";
5    char dst[10] = "Hi";
6    std::strcat(dst, src);
7    std::cout << dst << "\n";
8    return 0;
9}

What does this program output?

1#include <iostream>
2int main() {
3    int matrix[2][3] = { {1,2,3}, {4,5,6} };
4    int sum = 0;
5    for (int r = 0; r < 2; ++r) {
6        for (int c = 0; c < 3; ++c) {
7            sum += matrix[r][c];
8        }
9    }
10    std::cout << sum << "\n";
11    return 0;
12}

What is the output of this std::string comparison?

1#include <iostream>
2#include <string>
3int main() {
4    std::string a = "apple";
5    std::string b = "banana";
6    if (a < b) std::cout << "less";
7    else std::cout << "not less";
8    std::cout << "\n";
9    return 0;
10}

Find the bug related to C-style strings

Click on the line(s) that contain the bug.

#include <iostream>

#include <cstring>

int main() {

    char *name = "Alice";

    name[0] = 'M';

    std::cout << name << "\n";

    return 0;

}

Find the bug in this 2D array code

Click on the line(s) that contain the bug.

#include <iostream>

int main() {

    int rows = 2, cols = 3;

    int matrix[2][3] = { {1,2,3}, {4,5,6} };

    for (int r = 0; r <= rows; ++r) {

        for (int c = 0; c < cols; ++c) {

            std::cout << matrix[r][c] << " ";

        }

        std::cout << "\n";

    }

    return 0;

}

Click the line that risks buffer overflow for a C-style string

Click on the line to select.

#include <iostream>

#include <cstring>

int main() {

    char buf[5];

    std::strcpy(buf, "Hello");

    std::cout << buf << "\n";

    return 0;

}

Click the line where std::string concatenation happens

Click on the line to select.

#include <iostream>

#include <string>

int main() {

    std::string first = "C++";

    std::string second = "17";

    std::string combined = first + " " + second;

    std::cout << combined << "\n";

    return 0;

}

Fill blanks to read 5 integers into an array

Fill blanks to declare and initialize a C-style string with manual null terminator

Fill blanks to use std::string append and length

Fill blanks to declare and use a 2D array

Match each string type with its description

Click an item on the left, then click its match on the right. Click a matched item to unmatch.

Match each operation with the API it primarily relates to

Click an item on the left, then click its match on the right. Click a matched item to unmatch.

Order the steps to safely read input into a C-style string buffer

Drag and drop to reorder, or use the arrows.

Order steps to iterate over a 2D array and compute the total sum

Drag and drop to reorder, or use the arrows.